Satellite to get rid of orbiting debris

Swiss scientists said on Wednesday they plan to launch a " janitor satellite" specially designed to get rid of orbiting debris known as space junk.

The $11-million satellite called CleanSpace One - the prototype for a family of such satellites - is being built by the Swiss Space Center at the Swiss Federal Institute for Technology in Lausanne (EPFL).

EPFL said on Wednesday its launch would come within three to five years and its first tasks are to grab two Swiss satellites launched in 2009 and 2010.

The US space agency Nasa says over 500,000 pieces of spent rocket stages, broken satellites and other debris are being tracked as they orbit Earth.

The debris travels at speeds approaching 28,000 kmph, fast enough to destroy or inflict costly and timedraining damage on a satellite or spacecraft. Collisions, in turn, generate more fragments floating in space.

"It has become essential to be aware of the existence of this debris and the risks that are run by its proliferation," said Claude Nicollier, an astronaut and EPFL professor.

Building the satellite means developing new technology to address three big problems, scientists say. The first hurdle has to do with trajectory: The satellite has to be able to adjust its path to match that of its target.

Next, the satellite has to grab hold of and stabilize the debris at high speeds. And, finally, CleanSpace One has to be able to take the debris, or unwanted satellites, back into Earth's atmosphere, where they will burn on re-entry.